Trail of Cthulhu: Boundless Deceptions

Rules Cheat Sheet

The Keeper is the gm. Investigators are player characters. The Cthulhu Mythos is an awareness of the cosmos at large that wrecks the mind by sheer alienness.

Investigative Abilities
Give you core clues automatically. There are three categories: Academic, Interpersonal, and Technical. In a given scene, the Keeper may tell the player with a relevant ability a clue, or the player may trawl for clues by naming the ability they want to use. A clue may have several abilities that can be used to get it. An ability pool of 1 point is competent; 5 points, world class.

Point Spends
Player may spend 1 or 2 points from the Investigative pool to gain access to special benefits or supplementary clues: calling in favors, cutting red tape, making a contact, finding a tome, etc. A point spend allows a player creative input in the game world, or may be a keeper-planned part of the investigation.

General Abilities
Cover physical actions and contests with a strong element of the uncertain. Test an ability by a 1D6 roll against a difficulty of 2 to 8. Point spends from the general ability pool add to the roll, but deplete your pool and are lost no matter the outcome. Ability pools refresh in downtime between investigations.

Piggybacking
Happens when investigators act together, e.g. a hike or sneaking around. One investigator leads, spends points, and makes a test. The others spend 1 each: these are not added to the leader’s roll but give them the benefit of his success. Everyone who cannot pay 1 point increases the difficulty +2.

Cooperation
Possible on some tasks, e.g. breaking down a door or performing a ritual. Here, each assistant spends X points and adds X-1 to the leader’s roll.

Contests
For contests between characters, each makes a test. The first to fail loses the contest. The keeper determines the first actor; generally fleers roll before chasers; the lowest pool goes first in simultaneous acts. Characters act in order of pool size. An action other than an attack drops you to the end of the order. Roll Weapon against Weapon, Firearm/Firearm, etc. vs a hit threshold. Yours is 3, or 4 if your Athletics is 8+. Cover will raise or lower the threshold in a firefight. Investigators can choose to use non-lethal force in combat, unless wielding a bladed weapon or firearm.

On any hit, roll 1D6 for damage modified by the type of weapon. Armor subtracts from damage.

Hand Attacks: -2

Small, improvised weapons: -1

Bat, machete, pistol: 0

Axe, heavy gun: +1

Both barrels; autofire burst: +1

Point-blank range: +2

“Fish in a barrel”: x3

Health
Subtract damage from your Health pool. You are hurt at 0 to -5 points. Penalties: all difficulties are +1; investigative spends are impossible; make a test vs a difficulty equal to absolute value of Health to stay conscious. At -6 to -11 you are seriously wounded with no actions possible; make a 2nd consciousness test. You are dead at -12. Point spends from Health add to consciousness tests at the cost of further damage.

Each point spend from First Aid heals someone else 2 or yourself 1; recover 2 points per day of rest. Spending 2 points of First Aid will stabilize someone wounded but restore no Health. Convalesce for days equaling the absolute value of Health, then recover half your maximum Health.

Stability
Protects you from shock. Test Stability vs 4 for ordinary horror, vs 5 for Mythos events. If you fail, lose a stated amount from your Stability pool. Some mythos threats cause Stability loss even on a success! Point spends from the Stability pool may be worthwhile against far greater loss from a failed test.

You are shaken when Stability is between 0 and -5 (penalties as for hurt), blasted at -6 to -11 (fight or flight only, lose 1 permanent Stability); and permanently gaga at -12.

Blasted investigators may gain a madness like a delusion or an obsession, and/or become shell shocked: when facing the source of fear again, test Stability; on failure, you freeze up for 15 minutes and are shaken for 24 hours, but lose no Stability. Refresh someone else’s Stability by 2 with a Psychoanalysis spend; refresh your own by 1D6 with an appropriate Investigative spend and roleplaying that wows your friends.

Each investigator has a Drive leading them into situations normal people avoid; fighting the drive costs up to 4 Stability or 1/3 the current pool, whichever is worse; following the drive refreshes 1 or 2 points.

For every 3 points of Stability you may name one person as a Source of Stability. These are the people in your life who ground you; to whom you can turn with your troubles and concerns. Friends, family, or colleagues who provide you with motivation to continue fighting the good fight.

Sanity
The ability to believe in any part of the human world. You permanently lose points from the Sanity pool when failing Stability tests against Mythos threats. The worst phenomena cost some Sanity even on a success. At 0, the ability to act in a human frame of reference is gone.

Use the Cthulhu Mythos investigative ability to gain cosmic clues… at cost to both Sanity and Cthulhu Mythos pools, with no test. Once you have points in Mythos, maximum Sanity equals 10 minus Mythos. Denial of a Mythos event when there is no evidence remaining shaves 1 Sanity point off the loss; OR you can faint at first blush, lose only 1 Sanity, and gain some clue on recovery. While the keeper will not kill fainters, all else goes.

For every 3 points, define one Pillar of Sanity that the investigator centers his psyche on, like patriotism, art, natural law, etc. Losing 3 points of Sanity at once can be roleplayed as a pillar “crumbling.” With Sanity 2 or less, no pillars are possible and all stability tests are +1 difficulty.